The invention relates generally to a fastener for securing a pair of apertured members. In particular, it relates to a fastener for securing a pair of aligned, apertured panels and for maintaining those panels in an aligned condition.
Several fasteners are known which can secure panels of different thicknesses to one another. Even when the space between these panels is varied, one type and size of fastener is often all that is required, because of the number of axially spaced-apart wing elements along the fastener shank. Fasteners of this kind are shown in U.S. Pat. No. 3,810,279, issued to Swick et al, on May 14, 1974, hereinafter referred to as Swick. These fasteners comprise a head and a shank, the shank having a generally polygonal axially extending body portion providing a plurality of radially outwardly facing flat surfaces. The wing elements extend radially outwardly from the flat surfaces and engage the panels or apertured members. The shank and its body portion are generally smaller in cross-section that the apertures in the secured panels. The flexible wings, however, are long enough so that they will flex when inserted in an aperture and resume their normal unflexed position after passing through the aperture whereby some abuttingly engage the underside of one of the secured panels.
Because of the small cross-section of the shank, the fastener may be inserted in panels whose apertures are misaligned and will accommodate that misalignment through orientation into a tilted or non-normal position to those members. This feature of the Swick fasteners renders them utilizable for applications where misalignment of panel apertures is common and even desirable. However, there are other applications in which it is essential that the fastener maintain a normal orientation relative to the panel members, or in which the fastener aid in maintaining panel apertures in an aligned state.
Further, a fastener of the general type shown in the prior art and in other than the normal position is somewhat difficult to remove from the panel apertures. Although the shank itself does not abut the aperture periphery, the wings extending radially from the outwardly facing flat surface do. Upon insertion and removal of the tilted fastener, unequal forces will be imparted to those wings. The greater insertion or removal forces imparted to some of the wings may cause their breakage and thereby render the fastener useless.